verilator/test_regress/t/t_assert_nexttime.v

60 lines
1.8 KiB
Systemverilog

// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain.
// SPDX-FileCopyrightText: 2026 Wilson Snyder
// SPDX-License-Identifier: CC0-1.0
// verilog_format: off
`define stop $stop
`define checkh(gotv, expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d: got='h%x exp='h%x\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
// verilog_format: on
module t (
input clk
);
integer cyc = 0;
reg [63:0] crc = '0;
reg [63:0] sum = '0;
// Derive test signals from CRC
wire a = crc[0];
wire b = crc[1];
wire c = crc[2];
wire d = crc[3];
// Aggregate outputs into a single result vector
wire [63:0] result = {60'h0, d, c, b, a};
always_ff @(posedge clk) begin
`ifdef TEST_VERBOSE
$write("[%0t] cyc==%0d crc=%x a=%b b=%b c=%b d=%b\n",
$time, cyc, crc, a, b, c, d);
`endif
cyc <= cyc + 1;
crc <= {crc[62:0], crc[63] ^ crc[2] ^ crc[0]};
sum <= result ^ {sum[62:0], sum[63] ^ sum[2] ^ sum[0]};
if (cyc == 0) begin
crc <= 64'h5aef0c8d_d70a4497;
sum <= '0;
end else if (cyc < 10) begin
sum <= '0;
end else if (cyc == 99) begin
`checkh(crc, 64'hc77bb9b3784ea091)
`checkh(sum, 64'hdb7bc8bfe61f987e)
$write("*-* All Finished *-*\n");
$finish;
end
end
// =========================================================================
// nexttime: property must hold at the next clock tick
// =========================================================================
assert property (@(posedge clk) nexttime (1'b1));
assert property (@(posedge clk) nexttime (cyc > 0));
assert property (@(posedge clk) disable iff (b) nexttime ~c);
assert property (@(posedge clk) disable iff (~b) nexttime c);
endmodule